HIV treatment is an ongoing, complex process that takes a full commitment on your part. While so many HIV-positive people do well with medications, treatment success is not guaranteed. Because keeping up with meds can be difficult, treatment failure can occur. Treatment failure means that the regimen you are on is no longer working against the virus. This usually means that your viral load is detectable and is increasing, and that your CD4 cell count is decreasing.

There are several possible reasons that treatment fails. One reason is that patients can have a difficult time tolerating and adhering to their treatment regimen due to the side effects and/or the number of pills they have to take. But probably the most common reason for treatment failure is drug resistance — when HIV makes copies of itself that can "resist," or survive against, the meds you’re taking.


Understanding exactly how HIV becomes resistant to meds is a complex subject, but it can be broken down into a few simple parts.

First, HIV is a virus that can make copies of itself very quickly. But as it multiplies, the virus also has a bad habit of making genetic mistakes that change its shape and form. These mistakes, also known as mutations, are never corrected. The result is that your HIV infection is actually made up of a large number of different types, or strains, of the virus.

The meds available today can stop most, but not all, strains of HIV. So drug resistance develops when some strains with certain mutations are able to survive even though you're taking meds. In other words, mutations change the virus' shape and form letting it "escape" from the meds you're taking. Over time, these strains can become the most common ones in your body. Then in most cases, your viral load will go up, your CD4 cell counts will go down, and the risk of you becoming sick increases. If left uncontrolled, drug-resistant HIV can continue to multiply and can lead to AIDS.


Drug resistance can't be completely prevented, but there is one thing you can do to help avoid it: take your meds every day, exactly as prescribed by your healthcare provider. Proper adherence to your treatment regimen will give you the best chance against drug resistance by keeping your viral load down as much as possible and as long as possible. Partial adherence will lead to partial HIV control, which allows drug-resistant strains of the virus to survive and multiply.


If your viral load does not become undetectable while on a HAART regimen, your healthcare provider should do a drug resistance test. This will determine if the HIV in your body has mutated into a strain that your current treatment regimen can't control. Based on the results of the test, your healthcare provider can change the medications in your regimen to ones that may still work against the resistant HIV strains.

To learn more about treatment failure and drug resistance, talk to your healthcare provider.